diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index e5a50c82d3f903ceb587dea629085fcff3204a24..bb873069ffabbb63a8a71510a7dcdf848ba821f0 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -2,6 +2,13 @@
 Changelog
 =========
 
+Version 1.0
+-----------
+
+Version 1.0.0
+*************
+- Bug: Nested namespace definitions were present, which are a C++17 feature.
+
 Version 0.9
 -----------
 
diff --git a/include/ALL_Functions.hpp b/include/ALL_Functions.hpp
index e55ee226410c89ca360d0135cf76d7db636613ff..b8f9b6b930fb4fc1497938472f6f0cbb1dd6f8b4 100644
--- a/include/ALL_Functions.hpp
+++ b/include/ALL_Functions.hpp
@@ -5,7 +5,8 @@
 #include <cmath>
 #include <vector>
 
-namespace ALL::Functions {
+namespace ALL{
+namespace Functions {
 
 /// function to compute the one-dimensional shift of the border between the
 /// local process and the process indicated by neighbor_rank
@@ -65,5 +66,5 @@ T borderShift1d(const int remote_rank, const int local_coord,
   return shift;
 }
 
-}// namespace ALL::Functions
+}}// namespace ALL::Functions
 #endif